Optimization of the volume fraction of the NAPL, silicone oil, and biodegradation kinetics of toluene and DMDS in a TPPB

► The volume ratio between silicone oil and water was optimized through BOD5 measurements. ► Ratios ranging between 20 and 30% were optimal for toluene and DMDS removal. ► Toluene and DMDS removal was then efficient in a TPPB containing 25% silicone oil. ► NAPL presence led to 62 and 107% improvement of the biodegradation rate for toluene and DMDS.